Philips Semiconductors
DSPCPU Operations for TM1100
File: ops.fm5, modified 7/23/99
PRELIMINARY INFORMATION
A-87
IEEE status ags from convert oating-point to
integer using PCSW rounding mode
SYNTAX
[ IF r
guard ] ifixieeeflags rsrc1
→ rdest
FUNCTION
if r
guard then
r
dest
← ieee_ags((long) ((oat)rsrc1))
ATTRIBUTES
Function unit
falu
Operation code
122
Number of operands
1
Modier
No
Modier range
—
Latency
3
Issue slots
1, 4
DESCRIPTION
The ifixieeeflags operation computes the IEEE exceptions that would result from converting the single-
precision IEEE oating-point value in r
src1 to a signed integer, and an integer bit vector representing the computed
exception ags is written into r
dest. The bit vector stored in rdest has the same format as the IEEE exception bits in
the PCSW. The exception ags in PCSW are left unchanged by this operation. Rounding is according to the IEEE
rounding mode bits in PCSW. If r
src1 is denormalized, zero is substituted before computing the conversion, and the
IFZ bit in the result is set.
The ifixieeeflags operation optionally takes a guard, specied in r
guard. If a guard is present, its LSB
controls the modication of the destination register. If the LSB of r
guard is 1, rdest is written; otherwise, rdest is not
changed.
EXAMPLES
Initial Values
Operation
Result
r30 = 0x40400000 (3.0)
ifixieeeflags r30
→ r100
r100
← 0
r35 = 0x40247ae1 (2.57)
ifixieeeflags r35
→ r102
r102
← 0x02 (INX)
r10 = 0,
r40 = 0xff4fffff (–3.402823466e+38)
IF r10 ifixieeeflags r40
→ r105 no change, since guard is false
r20 = 1,
r40 = 0xff4fffff (–3.402823466e+38)
IF r20 ifixieeeflags r40
→ r110 r110 ← 0x10 (INV)
r45 = 0x7f800000 (+INF))
ifixieeeflags r45
→ r112
r112
← 0x10 (INV)
r50 = 0xbfc147ae (-1.51)
ifixieeeflags r50
→ r115
r115
← 0x02 (INX)
r60 = 0x00400000 (5.877471754e-39)
ifixieeeflags r60
→ r117
r117
← 0x20 (IFZ)
r70 = 0xffffffff (QNaN)
ifixieeeflags r70
→ r120
r120
← 0x10 (INV)
r80 = 0xffbfffff (SNaN)
ifixieeeflags r80
→ r122
r122
← 0x10 (INV)
OFZ
IFZ
INV
OVF
UNF
INX
DBZ
0
1
2
3
4
5
6
7
31
00
SEE ALSO
ixieeeags